﻿/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2021 Thomas Braun, Jens Klingen, Robin Krom
 *
 * For more information see: https://getgreenshot.org/
 * The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using Svg;

namespace Greenshot.Base.Core
{
    /// <summary>
    /// Create an image look like of the SVG
    /// </summary>
    public sealed class SvgImage : IImage
    {
        private readonly SvgDocument _svgDocument;

        private Image _imageClone;

        /// <summary>
        /// Factory to create via a stream
        /// </summary>
        /// <param name="stream">Stream</param>
        /// <returns>IImage</returns>
        public static IImage FromStream(Stream stream)
        {
            return new SvgImage(stream);
        }

        /// <summary>
        /// Default constructor
        /// </summary>
        /// <param name="stream"></param>
        public SvgImage(Stream stream)
        {
            _svgDocument = SvgDocument.Open<SvgDocument>(stream);
            Height = (int) _svgDocument.ViewBox.Height;
            Width = (int) _svgDocument.ViewBox.Width;
        }

        /// <summary>
        /// Height of the image, can be set to change
        /// </summary>
        public int Height { get; set; }

        /// <summary>
        /// Width of the image, can be set to change.
        /// </summary>
        public int Width { get; set; }

        /// <summary>
        /// Size of the image
        /// </summary>
        public Size Size => new Size(Width, Height);

        /// <summary>
        /// Pixelformat of the underlying image
        /// </summary>
        public PixelFormat PixelFormat => Image.PixelFormat;

        /// <summary>
        /// Horizontal resolution of the underlying image
        /// </summary>
        public float HorizontalResolution => Image.HorizontalResolution;

        /// <summary>
        /// Vertical resolution of the underlying image
        /// </summary>
        public float VerticalResolution => Image.VerticalResolution;

        /// <summary>
        /// Underlying image, or an on demand rendered version with different attributes as the original
        /// </summary>
        public Image Image
        {
            get
            {
                if (_imageClone?.Height == Height && _imageClone?.Width == Width)
                {
                    return _imageClone;
                }

                // Calculate new image clone
                _imageClone?.Dispose();
                _imageClone = ImageHelper.CreateEmpty(Width, Height, PixelFormat.Format32bppArgb, Color.Transparent, 96, 96);
                _svgDocument.Draw((Bitmap) _imageClone);
                return _imageClone;
            }
        }

        /// <summary>
        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        /// </summary>
        public void Dispose()
        {
            _imageClone?.Dispose();
        }
    }
}